Apparatus for cleaning cans



July 1, 1952 T. F. CLARK APPARATUS FOR CLEANING cANs 2 SHEETS-SHEET Filed Aug. 22, 1951 INVENTOR T. F. C LA R K BY 1n.

ATTORNEY Patented July 1, 1952 APPARATUS FOR CLEANING CAN S Thomas F.` Clark, Peoria, lll., assignor to the United States of America as represented by the Secretary of Agriculture Application August 22, 1951, Serial No. 243,146

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. '757) 2 Claims.

The invention herein described may be manufactured and used by or for the Government oi the United States of America for governmental purposes throughout the world without the payment to me of any royalty thereon.

This invention relates to a method and an apparatus for cleaning containers, such as metal cans. It particularly relates to cleaning metal milk cans prior to retinning,

Milk cans must be cleaned and reconditioned from time to time to remove milk residues, dirt, foreign material, rust and other corrosion residues prior to retinru'ng. The retinning of milk cans has heretofore resulted in an excessive nurnber oi rejected and recycled cans, because of faulty cleaning.

Prior to my invention, salvaging of cans, such as metal milk cans, has required a large amount of costly hand labor and chemicals. It has customarily included alkaline and acid treatments involving scrubbing and scouring with brushes, and steel wool, and, unless carried out with extreme care and skill, the hand cleaning, especially on inner surfaces oi the cans, often results in non-uniform cleaning and actual loss of the residual protective coating surfaces by abrasion and `chemical action.

According to this invention, means are provided ior cleaning milk and other cans, and cylindrical-type objects generally, by subjecting the surfaces to be cleaned to a blast of soft grits. The term soit grits as used herein refers to such materials as ground corncobs, pecan shells, filbert shells, walnut shells or similar materials. These grits, alone or in admixture with each other, maybe further mixed with varying proportions of rice hulls. Soft grit blasting is advantageous, since it effects removal of the objectionable materials from the can surfaces without damage to the container itself. This principle, when applied using the device oi this invention, makes possible rapid and uniform cleaning with a minimum oi hand labor. When so cleaned the can is ready for the light pickling operation prior to retinning. Frequently the pickling may be omitted and the can sent directly to retinning.

The novel apparatus is illustrated in the accompanying drawings.

Figure 1 is an assembled View of the cleaning blast chamber and pressure tank means to feed blasting grits thereto;

Figure 2 is a horizontal cross-section of the blast chamber, at plane 2-2 of Figure 3;

Figure 3 is a vertical cross section of the blast chamber;

Figure 4 is a'vertical section of a modiiied form of one-half of an air and grit mixing and feeding valve.

Referring to Figure 3, the apparatus is shown with a milk can l in cleaning position. The can rests on platform 2, which is a rotary table preferably made of a perforate grating and having an aperture 29B over which the open end of the can rests. Blast nozzles 20| and 262 are connected by means of supporting pipes lill and lili and `flexible connections 203 and 2M with a source 22 of a mixture of air and grits. The blast nozzles are each secured rigidly to bracket members 5 and E situated in guiding groove I5 oi elevating mechanism I6. These bracket members have screw threaded bores that mesh with vertical worm shaft 'l which is driven by worm-and-gear arrangement 8. Shaft 8d drives the worm-andgear arrangement, thus causing members 5 and 6 to move in a vertical direction. Shaft 3i) is connected to a power source through a reversing mechanism, not shown, so that brackets 5 and (i and the nozzles move up and down in oscillatory manner. The reversing mechanism is adjustable, by means well known in the art to raise and lower the blast nozzles the proper distance for blast-cleaning the entire length of the can. Nozzles 20| and 2&2 enter the blast chamber through vertically movable wall sections 39| and 3&2 that restrain the soft grits within the chamber, yet allow vertical motion required of the nozzles and their lines. Sections 35i! and 362 need not be in vertical alignment, to avoid interference.

Cooperating with the vertical movement of the nozzles, table 2 rotates so that the entire surface, inside and out, of the can is eiiectively blasted by the nozzles. The table is made to rotate by V-belt drive 265, the V-shaped groove 2236 encircling the table. The rotating table is supported upon rollers 9 and is centered by rolling guide members It. The guide members have an overhanging flange at ll to guide the outer edge of the table.

The blast cleaning mechanism is provided with a housing I2 having an upper dust outlet la! and a lower recovery hopper I3.

As may be seen from the drawings, my apparatus consists essentially of a rotating table upon which cans to be cleaned may be placed.. In operation, a system of multiple blast nozzles, for blasting inside and outside the can, move vertically with respect to the can so that effective cleaning is obtained over all the surfaces of the can.

Milk cans are frequently cleaned after the bottoms have been removed. Cans in this condition may obviously be placed upon the rotating table in either upright or inverted position. Moreover, my apparatus may be constructed in a simplied variation to clea'n'bottomless cans. vLibr-example, nozzle 20| maybe constructed to enter the can from above by obvious variations in construction of the worm shaft. This modified construction eliminates the necessity for theopening in-the rotating table. Y. u

In operation, used blasting v'gritsfiall fromfthe zone of blasting and are"recovered'for `rel-use from the recovery hopper and fed back into the tank 20, by any suitable Vvscrew Vconveyor (not shown). l

Casing 20 is a pressurized tank containing soft grits. The grits ow through, grit Y'c-ontrol'valve 2| into duplex manifold 22"wh-ichl is'af mixing chamber for grits from?! and air from I9. This supplies streams ofV grit for liiexible lines 203'and 204. Dust from lthe cleaning chamber 'is eX- hausted by means of exhaust blower sending the dust through line 26 to av dust collector,- not shown. Usedgrits are" removed from the cleaning chamber through Ydump ,valve lrl.

Figure 4 illustrates a. modied form 'of my invention in which the pressurized tank is eliminated. Inl this variation adouble or duplex `mixing valve-2 replaces the dumpt valve l1.

This permits Vcontinuous recycling of grits from vthe hopper i3 ofjthe cleaning apparatus back through 'the'.exible, lines tothe blast nozzles. Compressed-air is fed through line2 v to nozzle v 33. Grits are received through opening r(20 directly from hopper I3. Auxiliary air from the atmosphere enters Ythrough auxiliaryv air inlet 30.

Figure 4 represents apro-ss Vsectionof one-half of the mixing valve. Each zhalf isArvdesligned to feedone of ileXible` lines-20,3 and Y204. Suitable valves commonly known in the art are used as a means for regulating the air which in turn controls the `flow ofgrits. A N

It will be obvious to' anyone skilled in the art :that eitherthey rotati'ngutable orthe multiple nozzle system` mayeinove vertically. Tt'isfonly necessary that there be Vrelative `vmovement` ASimilarly, theremmaybe more than two* blast nozzles, 'and they "n'ay be cnstructed" to" best direct 'theleai'iing "blastv against-specifalVv shapes and surfaces rvto becleaned. Mreoverfthe speed of vertical"i'novementmay be variable. -This' can be accomplished'by well-known mechanisms 1cooperating with theVV reversing 'mechanism' and Vthe drive shaft. The particular means for'4 accomplishing Vthe rotating motion Iof theft'able and the' vertical'movem'ent may vary widely.

` Likewise, the'rotation of the' can'with" respect to the nozzle system* may `be accomplished" by hrotating the nozzle system with respect"tffthe table.

Yactuated" elevating mechanisms. IOthenvfariations in construction will be apparent `to"those skilled in 'theart. and-arewith'in thel 'scope of f my invention.

I claim: 1 l.J Anapparatus for' blast cleaning"t'he"inner 'and outer surfaces of ia' 'vesselr comprising: a

said opening, means for turning vthe `table,1sup porting rollers below the tabla/guide means'or surface of the vessel, means for turning the table,

a supporting conduit connected to each nozzle, the conduit for the inner nozzle passing upwardly through the opening in the table, the supporting 'c'onduitspassing'laterally through the housing 'side"wall,"Ineans"m-ounted outside the housing to raise and l'owr the two supporting conduits substantially the length of the vessel to be cleaned,

plate" means movable with each conduit on the said housing fwall'to keep the Wall closed, pasag'eWaysfadjacent the periphery of the table permitting the egress of air upwardly in the housing outside the-vessel being cleaned-an air- --dust vent -for the housingl-above'the table, means `for lwithdrawing -air and dust'through' said vent, vair-grits Amixing means to' supply'a lblast -ofair and cleaning gritstoeach of fsaid-conduitsand thence to the nozzles, supportingrollermeans belovv'and adjacent the periphery-"of the table, guidefmeans for the: periphery'offthe.l table; and a hopper attached to the lower part-'of` vthev housing' to collect the'spent': grits-v below the table.

2.An apparatus-for `blast cleaning the` inner land outer surfaces of a ve'sselfcomprising:` a housing, Va rotatable table' withinF-the housing 'adapted -to fsupport the vessel vandhaving a central lopening which communicates with the inside of the vessel, an outer blast :nozzle directed inwardly to clean the outer surface 'of' the vessel, an inner blastnozzle directed outwardlyto clean the inner surfaces AofV the fvessel;v an'. inner' blast nozzle feed -pipe projecting upwardly" through the periphery of the table. means :for reciprocatingboth of the'nozzles `thelength of the vessel, fair-grits 'mixing means to supplyablastfof'air and cleaning grits-to saidnozz'1es,aidustfand air outlet for the part of the' housing above the table,

andfair passages adjacent therperimeteriofthe ytable to :permit upward vmovement -of air to-said outlet.

"REFERENCES CITED The following references are AVof' record 4inthe file `of this patent:

L UNITED' STAT-Es' i PATENTS 

